1. Field of the Invention
The present invention relates to a computer system and a control method thereof, more particularly to a computer system capable of confirming if a plurality of memory buses are operated in a multi-channel mode and a control method thereof.
2. Description of the Related Art
A computer memory has two basic types. One is a random access memory (RAM) and the other is a read only memory (ROM). The RAM is generally used for reading and writing data by a processor. The RAM is a typical volatile memory, that is, data stored therein is lost if power is cut off. The ROM is generally used for storing non-changeable data, such as a basic input/output system (BIOS). The ROM is a typical non-volatile memory, that is, data stored therein is not lost even if power is cut off.
In particular, the RAM is considered a dynamic RAM (DRAM) type, because it needs frequent recharging or refreshing to preserve/maintain content therein. A plurality of RAMs arranged on a small circuit card are referred to as a “memory module”. A currently widespread module type DRAM has a plug that is inserted into a memory socket connected to a main board or a memory carrier card in a computing device. Some examples of current memory modules are: a fast page mode (FPM) module, an extended data out (EDO) module, a synchronous DRAM (SDRAM) module, a Rambus DRAM (RDRAM) module, a double data rate SDRAM (DDR SDRAM) module, and so on.
In the case of using two or more memory modules, a dual channel mode memory module configuration that theoretically shows a twofold efficiency for same memory capacity as a single channel mode memory module configuration has been adopted to improve efficiency when using two or more memory modules. In the dual channel mode, respective memory modules are separated into two channels and used in parallel, advantageously accomplishing a twofold memory bandwidth using the currently available memory modules.
Operation in the dual channel mode is based on the assumption that memory modules connected to both channels are mutually compatible. Therefore, in case critical features between the memory modules connected to each channel are different, the dual channel mode cannot be performed. For example, memory modules of manufacturers have features, such as various device structures and logical banks according to manufacturer thereof or kinds of memories, which differ from each other, and cannot work in the dual channel mode if they are connected to each channel. Also, in the case that memory capacities of respective channels are different, for example, a memory capacity of a first channel is 128 MB while a memory capacity of a second channel is 64 MB, the dual channel mode cannot be performed.
Further, a computer operating in the conventional dual channel mode, does not have a method of confirming whether the memory system is operating in the dual channel mode. Thus, although a computer operates in the dual channel mode, there is a problem that operation efficiency is decreased, in case the memory modules are not correctly arranged.